Lengthy surveys take more time and induce the use of undesired response styles. Response styles generate biases in responses, particularly in lengthy surveys (Baumgartner & Steenkamp, 2001). Response style is defined as tendency to systematically respond to questionnaire items regardless of item content (Baumgartner & Steenkamp, 2001). In practice, market research agencies prefer to use split questionnaires where questionnaires split into parts and each subset is administered to a randomly selected group of respondents (Raghunathan & Grizzle 1995). So far, split questionnaire design literature has been mainly investigated estimation and inference (Lord, 1962; Shoemaker, 1973; Merkouris, 2014; Chipperfield, Barr, & Steel, 2017), data imputation (Raghunathan & Grizzle, 1995; Rässler et al. 2002), and optimal designs (Thomas et al. 2006; Adıgüzel & Wedel 2008; Gonzalez & Eltinge, 2008; Chipperfield & Steel, 2009; Chipperfield & Steel, 2011). Despite split questionnaire is recommended to reduce undesired response styles, its relationship with response styles remains unclear. Two methods of optimal split questionnaire designs were proposed (Adıgüzel & Wedel, 2008): 1) Between-block design: To select entire blocks of questions, 2) Within-block design: To select sets of questions in each block. In this paper, we examine empirically how split designs lessen different type of response styles. Our findings indicate that split questionnaires reduce acquiescence balance, and disacquiescence relative to full questionnaires. The within-block split surveys reduce disacquiescence, acquiescence and balance, whereas the between-block ones did not. Stylistic responding is also influenced by questionnaire satisfaction, attitude, length and mood. Disacquiescence is negatively correlated to mood, questionnaire length and attitude. Midpoint is positively correlated to length, but negatively to questionnaire satisfaction, while acquiescence is opposite for both.

• Adıgüzel Feray(LUISS Guido Carli University, Italy)